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Old 02-11-2005, 10:19 AM   #1
Homer Glemkin
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neighbor table overflow


I'm running Redhat 8

Just started getting a neighbor table overflow error and I'm not sure how to go about and correct this.

/var/log/messages:
Feb 11 09:42:34 mail kernel: NET: 5 messages suppressed.
Feb 11 09:42:34 mail kernel: Neighbour table overflow.
Feb 11 09:42:35 mail kernel: Neighbour table overflow.
Feb 11 09:42:35 mail kernel: NET: 1 messages suppressed.
Feb 11 09:42:35 mail kernel: Neighbour table overflow.
Feb 11 09:42:40 mail kernel: NET: 18 messages suppressed.
Feb 11 09:42:40 mail kernel: Neighbour table overflow.
Feb 11 09:42:45 mail kernel: NET: 25 messages suppressed.
Feb 11 09:42:45 mail kernel: Neighbour table overflow.
Feb 11 09:42:50 mail kernel: NET: 17 messages suppressed.
Feb 11 09:42:50 mail kernel: Neighbour table overflow.
Feb 11 09:42:55 mail kernel: NET: 27 messages suppressed.
Feb 11 09:42:55 mail kernel: Neighbour table overflow.

After some google searches and I found it might be with my localhost, and it was messed up. If I run ifconfig I get:
eth0 Link encap:Ethernet HWaddr 00:C0:F0:3F:73:5F
inet addr:123.123.16.74 Bcast:123.123.255.255 Mask:255.255.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:159074 errors:1 dropped:0 overruns:0 frame:0
TX packets:111691 errors:4 dropped:0 overruns:0 carrier:4
collisions:0 txqueuelen:100
RX bytes:19602370 (18.6 Mb) TX bytes:83888714 (80.0 Mb)
Interrupt:3 Base address:0x8000

eth1 Link encap:Ethernet HWaddr 00:50:8B:E75:9E
inet addr:***.***.***.*** Bcast:***.***.**.*** Mask:255.255.255.***
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:123090 errors:0 dropped:0 overruns:0 frame:0
TX packets:147730 errors:0 dropped:0 overruns:0 carrier:0
collisions:531 txqueuelen:100
RX bytes:74218318 (70.7 Mb) TX bytes:14937203 (14.2 Mb)
Interrupt:11 Base address:0x1000

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:4627 errors:0 dropped:0 overruns:0 frame:0
TX packets:4627 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:447432 (436.9 Kb) TX bytes:447432 (436.9 Kb)
but when I run ifconfig restart I get :
error fetching interface information: device not found
Am I chasing the right thing here, or are these 2 different problems? How do I go about an fix this

Thanks,
Homer

Last edited by Homer Glemkin; 02-11-2005 at 01:41 PM.
 
Old 02-14-2005, 08:34 AM   #2
Homer Glemkin
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I have also noticed a slow down wihen connecting to and internet site, not sure if arp would cause named to mess up also
 
Old 10-22-2005, 11:15 PM   #3
Riddick
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Did this ever get solved?
 
Old 10-23-2005, 05:25 AM   #4
sats
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There are 2 possible reason for your problem one is that some of the machine in your network try to ping another machines which generates lots of packet.End another reason could be that your Arp cache size is small.
you can try the two following thinks.

do a TCPDUMP on your ethx interace and find out which is generated lots of packet.
Another thing which you can do is try to increase the size of your Arp cache.
by using the following command.
echo 1024 > /proc/sys/net/ipv4/neigh/default/gc_thresh1
echo 2048 > /proc/sys/net/ipv4/neigh/default/gc_thresh2
echo 4096 > /proc/sys/net/ipv4/neigh/default/gc_thresh3

try this out
Pls find out that one of the machine in your network is sending lots of packets REMOVE it
if u find out one.
Thanks
Satoo
 
Old 10-23-2005, 09:00 AM   #5
Riddick
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Ok, I'll try to see!
 
Old 10-23-2005, 02:28 PM   #6
Homer Glemkin
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Nope but that makes sense why we get that problem, because we have an alpha box in the network which is constantly broadcasting
 
Old 10-23-2005, 03:38 PM   #7
Riddick
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How do you mean?
We have 2 users using downloading programs that typically
have a lot of connections, and everything seems to block!

Is there a way around this?

Those enlargements I've made don't seem to make much of a difference!

Riddick
 
Old 11-02-2005, 09:35 AM   #8
Homer Glemkin
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I also read that earleir versions of the 2.4 kernel caused this also.
 
Old 11-02-2005, 06:37 PM   #9
Riddick
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I am running a 2.4.31
 
  


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